Bearing means



W. C. MARCHAND BEARING MEANS March 20, 1962 2 Sheets-Sheet 1 Filed July13, 1959 mimm INVENTOR.

WILLIAM C. MARGHAND ATTORNEYS March 20, 1962 w. c. MARCHAND 3,025,154

BEARING MEANS Filed July 13, 1959 2 Sheets-Sheet 2 FLUJD PRESSURE PuaPFIG.4.

INVENTOR.

WILLIAM C MARCHAND ATTORNEYS United States Patent ()fiflce 3,026,154Patented Mar. 20, 1962 3,026,154 BEARING MEANS William Charles Marchand,Detroit, Mich., assignor to Continental Aviation and EngineeringCorporation, Detroit, Mich, a corporation of Virginia Filed July 13,1959, Ser. No. 826,804 4 Claims. (Cl. 308-35) :My invention relates toanti-friction bearings and more particularly to a means of supporting anair or other fluid pressure bearing carried rotating member until aspeed is attained at which the fluid pressure bearing becomesoperatively effective.

The use of fluid pressure lubricated bearings such as air bearings posescertain problems which heretofore have either not been recognized or, ifrecognized, never effectively solved. *One difficulty is encountered infields such as gas turbines or other prime movers in which the fluidpressure for the fluid pressure bearing is produced by operation of themachine. Thus, until the machine reaches operative speed, pressurizedfluid for the bearing must be obtained from some other source such as acompressed air tank or an auxiliary pump carried by the vehicle orengine, driven from some source entirely divorced from the engine.

Another problem is that until the fluid pressure bearing supported partsare rotating at a certain minimum speed, dependent on fluid pressure andbearing clearance, the fluid will not adequately support the rotatingelement, so that friction between the moving parts is apt to cause heatand scoring.

An object of the present invention is to solve the aforesaiddifficulties by providing an improved and simplified combination of afluid pressure bearing and mechanical bearing.

Another object of the invention is to facilitate use of fluid pressurebearings by providing a supplemental mechanical bearing operable tosupport the rotating parts until such time as the fluid pressure bearingbecomes operatively effective.

For a more complete understanding of the invention reference may be hadto the accompanying drawings illustrating preferred embodiments of theinvention in which like reference characters refer to like partsthroughout the several views and in which FIG. 1 is a fragmentarycross-sectional view of supporting and rotating components embodying thepresent invention.

FIG. 2 is a cross-sectional view taken substantially on the line 2-2 ofFIG. 1.

FIG. 3 is a fragmentary cross-sectional detail view taken substantiallyon the line 3-3 of FIG. 2 but illustrating an altered position of themechanical bearing.

FIG. 4 is a cross-sectional view illustrating another modification ofthe invention.

FIG. 5 is a cross-sectional view taken substantially on the line 55 ofFIG. 4.

For convenience, the fluid pressure bearing is shown and described as anair bearing, although other gases or liquids will be as effective.

As illustrated in FIGS. 1-3, supporting structure portions and 11 arearranged to carry a rotating element or shaft 12. The portion 10 isarranged to have a clearance 13 between it and the element 12 to providean air bearing. Air or other fluid is pressurized by any means such as apump 14 and delivered to an annular groove 15 for supplying fluidpressure into the clearance space 13.

The present components may be part of a gas turbine or the like which isoperable when running to drive the air pressure pump 14. In such anarrangement, air would not be delivered until the turbine was inoperation.

The supporting portion 11 is provided with a bearing surface 16 formingan inner race for running elements or bearings 17 which are engaged withthe portions 18a and 18b of an outer split race 18 carried in a recess19 of the rotating element 12. One portion 18a abuts an inner shoulder20 of the recess 19, while the other portion 18b is resiliently urgedinwardly by any means such as a compression spring 21 abutting aretainer ring 22. Thus the bearings 17 are resiliently urged intorunning contact with the bearing surface 16 of the support portion 11,and act to support the rotating element 12.

The bearings 17 are, however, responsive to speed of the rotatingelement 12 due to centrifugal forces acting on the bearing 17, and thecomponents are so arranged that shortly after the speed of the rotatingelement 12 is attained at which the air bearing is effective to supportthe element 12, the bearings 17 move out radially to force the outerrace portion 18b against the spring force, axially separating the outerrace portions 13a and 18b so that the bearings 17 are disengaged fromthe bearing surface 16 as shown in FIG. 3.

Immediately as the bearings 17 are no longer in contact with the surface16, they are no longer restrained and will immediately tend toward thespeed of rotation of the ele ment 12, whereby centrifugal force on thebearings 17 increases to effect even more positive disengagement, sothat there will be no intermediate stage at which the bearings wouldtend to oscillate between the engaged and the disengaged positions.

When the speed is reached at which the mechanical bearing is disengaged,the air bearing, having all the well known advantages of substantiallyfrictionless support, is fully operative by itself. At this speed also,the air pump, if dependent on operation of the turbine as indicatedabove, will be able to supply the required air for the air bearing, thuseliminating all need for other starting air sources.

In FIGS. 4 and 5, a simplified modification is shown as comprisingsupporting portions 30 and 31 arranged to carry a rotating shaft 32. Asin the previously described structure, a clearance 33 is providedbetween the shaft 32 and the supporting portion 30 to provide an airbearing, and air is supplied under pressure from an air pump 34 to anannular groove 35.

The supporting portion 31 is provided with a bearing surface 36 formingan inner race for bearings 37. The shaft 32 is provided with arelatively thin cylindrical portion 38 which has a groove 39 forming anouter race for the bearings 37. The portion 38 is constructed toresiliently force the bearings 37 radially inward into engagement withthe bearing surface 36 providing for a no clearance mechanical bearingoperable at slow speeds. The outer end of the cylindrical portion 38 isprovided with a relatively heavy radially extending segmented flange 40,which is preferably formed in one piece and then segmented by cutting aplurality of equally spaced slots 41 as shown in FIG. 5. An annular ring42 is carried by the shaft 32 and is radially spaced from the segmentedflange 40 as at 43.

In operation, as the shaft 32 picks up speed, centrifugal forces act onthe bearings 37 and the flange 40 to throw the segments of the flange 40outward, radially stretching or extending the relatively thincylindrical portion 38 to cause a clearance for the bearings 37, atwhich time the shaft 32 will become wholly supported by the fluidbearing. The clearance between the segmented flange 40 and the annularring 42 is small enough so that contact is made between these membersbefore excessive stress is incurred in portion 38.

Although I have described only two preferred embodiments of myinvention, it will be apparent that various changes and modificationsmay be made therein without becomes operatively elfective, and meanssupplying fluid under pressure to said fluid pressure bearing.

2. A hearing means for supporting a rotating element, comprising asupport structure having a small clearance with respect to said rotatingelement to provide a fluid pressure bearing, mechanical bearing surfaceelements carried by said rotating element and by said support structure,running members between said bearing surface elements, means resilientlyurging said running members into bearing contact with said bearingsurface elements, said running members being operable in response'tocentrifugal forces to axially separate said bearing surface elements anamount sufl'lcient to disengage such from one of said bearing surfaceelements due to centrifugal forces shortly after said rotating elementattains a speed at which said fluid pressure bearing becomes operativelyeffective.

3. A bearing means for supporting a rotating element, comprising asupport structure having a small clearance with respect to said rotatingelement to provide a fluid pressure bearing, mechanical bearing surfaceelements carried by said rotating element and by said support structure,running members between said bearing surface elements, the bearingsurface element carried by said rotating element comprising an outersplit race, means resiliently urging the portions of said splitracetogether to thereby urge said running members into engagement with theother bearing surface element carried by said support structure, saidrunning members being responsive to centrifugal force and operable toseparate said split race and to disengage from the bearing elementcarried by said support structure due to attaining sufiicientcentrifugal force shortly after said rotating element attains a speed atwhich said air bearing becomes operatively effective.

4. A bearing means for supporting a rotating element, comprising asupport structure having a small clearance with respect to said rotatingelementrto provide a fluid pressure bearing, bearing surface elementscarried by said rotating element and by said support structure, runningmembers between said bearing surface elements, the bearing surfaceelement carried by said rotating element being operable to resilientlyurge said running members into noclearance bearing contact with theother bearing surface element carried by said support structure duringrelatively slow speeds at which said fluid pressure bearing'isinoperative and centrifugal forces acting on thebearing surface elementcarried by said rotating element being operable at relatively higherspeeds to resiliently urge's'aid bearing surface elements apart and todisengage said running members from the other bearing surface elementcarried by said support structure.

Bunnell Dec. 5, 1939 Gerard Dec. 30,1952

